A Solution to a Slippery Slope: CO2 Sleds on Mars?
Ever since high-resolution images of Mars’ surface have become available, scientists have wondered about the cause of long gullies seen running down along the slopes of ridges and crater walls. Here on Earth such features are often created by water flowing downhill, carving channels as it goes — but on Earth similar features usually end in fans of deposited material, while on Mars the channels simply just… stop.
To search for an answer to this mystery, NASA researchers took a field trip to some southwestern sand dunes and saw what happened when they sent various materials sliding down the slopes. As it turns out, dry ice — that is, frozen carbon dioxide, which is plentiful on Mars — does a very nice impression of a sled, picking up considerable momentum on black diamond and bunny slopes alike. The reason? Sublimation creates a pocket of gas that the slab of solid…
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